The process of resistance welding, with or without structural adhesives, is used to join adjacent sheet metal panels or other metal components. In conventional resistance welding processes, such panels are clamped together between opposing welding electrodes. Electrical welding current is then passed between the electrodes through the panel/component material. The dynamic resistance of the material generates intense heat at the faying interfaces of the work piece, i.e., any substrate-to-substrate interfacing surfaces, as well as at any electrode-to-work piece interfaces. The heat momentarily melts the panel material at the faying interfaces. When the material cools, a solid weld nugget is formed. Adhesive materials are often used at the faying interfaces to strengthen the weld nugget in a process referred to as weld bonding.
Historically, the presence of sparks in a resistance welding process has provided a type of visual assurance to a welding operator that a weld nugget of sufficient size was formed. The sparks themselves are expelled droplets of molten metal commonly referred to as weld spatter. Weld spatter material is cleaned from any cosmetic appearance surfaces of the work pieces during production, e.g., from the finished external metal show surfaces of an automotive body panel. Additionally, some metal work pieces are drawn through a bath of electro-coating material after the resistance welding/weld bonding process is completed. Accumulated weld spatter tends to separate in the bath and accumulate in the bottom of the tank. Cleaning of accumulated weld spatter and/or of the bath tanks results in additional down time and other process inefficiencies.